Detection of Isolated Vibration Spectrum Patterns Generated in Hull and Shafting Lines which Result Shipboard Faults

The origin of shipboard hull vibrations is dominantly determined by vessels propulsion system, main machinery, auxiliary systems, pumps, breaking of the waves at the ship hull, etc. When the ships are classified on various sizes and limitations, they demonstrate multiple characteristics of vibration signatures mainly based on the functionality of main machinery and ships’ hull. The vibration signatures generated from hull is a clear representation of the ships health and crew habitability.  The paper is focused on to a case study that the hull of a naval vessel which had undergone a major repair was inspected for suitability for further use in terms of vibration and habitability. The transferred vibration signature of the vessel was analyzed using vibration spectra in machinery and hull aspects. The measuring was done simultaneously with multi-channel measurements of the vessels vibrations at few characteristic positions.  Sea trials at following variable conditions had been carried out onboard the selected vessel. Sea State : 2-3; Loading Condition : Half Load; Wind Condition : Moderate< 15 knots; Sea Direction : Ahead, Astern